A box that uses human scent to trap and kill mosquitoes at night promises malaria protection for people working and relaxing outdoors.

The Mosquito Landing Box emits a smell that attracts Anopheles mosquitoes, which can transmit malaria. Once inside the box, the insects are infected with deadly fungi or covered in insecticide, or electrocuted if the box is hooked up to solar panels and a battery. The device was developed by researchers at the Ifakara Health Institute in Tanzania.

This is particularly important in Sub-Saharan Africa, where many people spend time together outside at night to cook, talk or catch news on communal TVs and radios.

The boxes work by releasing human scent, along with a small dose of carbon dioxide that simulates human breath. This mixture is spread by solar-powered fans.

Each synthetic human-scented bait can last for a month and, according to Arnold Mmbando, a researcher at the Ifakara Health Institute and the lead author of the paper, the smell is not unpleasant for humans nearby.

The boxes can attract mosquitoes over an area of 100 square metres with the prototypes costing between US$100 and US$150.

Mmbando says the solar panels can also provide electricity for villages during the day when Anopheles mosquitoes are not out feeding.

“The device was invented here in the southeastern part of Tanzania, and right now we are looking for funding and partners to scale up production and sell it to other countries,” he says.

To test their device, the researchers released 400 mosquitoes in a controlled space simulating a natural ecosystem containing several volunteers and two boxes: one with insecticide and one with mosquito-killing fungi. There was also a control chamber with volunteers but no boxes.

In tests, the insecticide box killed up to 63 per cent of mosquitoes, while the one with fungi killed about 43 per cent, the research team found. The mosquitoes also preferred the scent of the box to the scent of the people in the room.

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Steven Harvey, a researcher at Johns Hopkins Bloomberg School of Public Health in the United States, says the battle to defeat malaria needs extra measures beside bed nets and indoor insecticide sprays, which fail to deal with the problem of biting when people work or sit outside at night.

“People talk about spatial repellents and insecticide-treated clothing, for example, but right now we don’t have anything that really works outdoors,” he says.

But Harvey adds that the box must be tested in real life before being rolled out, and that the price tag is too high. “It’s a technologically complex solution, and it will have to be done at a reasonable cost,” he says.